Learning Forum

[Amir]

Hello, I am modeling a chamber which has fluid inside it and I want to model the circulation of fluid. Flow enters the pipe (-Y direction) and passes through it where it thermally interacts with the surrounding medium underground, and it exits from the other end of the pipe (+Y direction) which is inside the chamber. This cycle repeats in  atransient simulation. Which boundary conditions should i use for the entrance and the exit of the pipe?

Thanks

[Rob]

Probably interior. How does the system push/pull gas through the pipe? 

[Amir]

Thnak you Rob. In the real scenario it is going to be a fan sending gas down into the pipe. So it is gonna be interior fan BC at entrance, right?

and outflow at exit?

[Rob]

Interior at the exit, fan may be suitable for the inlet: they're not really designed to cover the whole cross section so stability may be an issue. 

A (pressure) outlet is an external boundary, not useful inside the domain. Do NOT use outflow.